1 PROPOSED SUPPLEMENTAL MITIGATED NEGATIVE DECLARATION
REGARDING ENVIRONMENTAL IMPACT
CITY OF BRENTWOOD
WASTEWATER TREATMENT PLANT PHASE II EXPANSION PROJECT
City of Brentwood Public Works-Engineering
1. NOTICE IS HEREBY GIVEN:
That the project described below has been reviewed pursuant to the provisions of the California Environmental Quality Act of 1970 (Public Resources Code 21100, et seq.) and a determination has been made that it will not have a significant impact on the environment.
2. PROJECT NAME: Wastewater Treatment Plant Phase II Expansion Project
3. DESCRIPTION OF PROJECT:
The City initiated planning for the Phase II wastewater treatment plant (WWTP) expansion project in 2016 to expand the treatment capacity from 5 million gallons per day (MGD) average dry weather flow (ADWF) to 7.5 MGD ADWF (Project). The City prepared an Initial Study to evaluate potential environmental impacts from construction and operation of the Project and adopted a Mitigated Negative Declaration (MND) on August 9, 2016. As originally proposed, the Project involved construction of a biosolids dryer building and storage silo as a means of producing Class A biosolids, thus facilitating additional uses or disposal methods for the biosolids. The City has since decided to use different technology and place the biosolids drying facilities at a different location. The project modifications consist of the following main components.
1. Installation of a biosolids drying and pyrolysis system (BDPS) outside of the existing footprint of the WWTP.
2. Realignment of a paved connector path to the Marsh Creek trail.
3. Installation of new WWTP perimeter fencing around the BDPS.
4. Tree removal.
All project components would be constructed on 4 acres of City-owned property immediately adjacent to the east boundary of the current WWTP footprint.
4. LOCATION OF PROJECT:
The Project is located in the City of Brentwood.
City of Brentwood Wastewater Treatment Plant Phase II Expansion Project Proposed Supplemental Mitigated Negative Declaration
Regarding Environmental Impact
2 5. NAME AND ADDRESS OF PROJECT PROPONENT:
City of Brentwood, Public Works-Engineering, 150 City Park Way, Brentwood, California 94513
6. FINDINGS
In accordance with Section 15074(d) of the California Environmental Quality Act (CEQA) Guidelines, the City Council adopted a Mitigated Negative Declaration and Mitigation Monitoring and Reporting Program (MMRP) for the City of Brentwood Wastewater Treatment Plant Phase II Expansion Project (Project), CIP Project No. 592-59140 in Resolution 2016-109, on August 9, 2016. The Mitigated Negative Declaration and MMRP included mitigation measures incorporated into the Project to reduce impacts of the Project to a less than significant level.
A Supplemental Initial Study has been prepared to assess the modified Project’s potential effects on the environment, and the significance of those effects. Based on the Supplemental Initial Study, the Project would not have any significant effects on the environment once mitigation measures are implemented. This conclusion is supported by the following findings.
1. The Project would have no impact to Agriculture and Forestry Resources; Hazards and Hazardous Materials; Land Use and Planning; Mineral Resources; Population and Housing; Public Services; and Utilities and Service Systems.
2. The Project would have less-than-significant impacts to Aesthetics; Air Quality; Energy; Greenhouse Gas Emissions; Public Services; Recreation; Transportation; and Wildfire.
3. Impacts of the Project would be less than significant with incorporation of the mitigation measures to Biological Resources; Cultural Resources; Geology and Soils; Hydrology and Water Quality; Noise; and Tribal Cultural Resources.
The mitigation measures identified in the Supplemental Initial Study that the City will implement to avoid or minimize potential environmental impacts are provided below. Implementation of these mitigation measures would reduce the environmental impacts of the Project to a less than significant level.
7. DOCUMENTATION
The attached Supplemental Initial Study documents the reasons to support the above Findings.
8. MITIGATION MEASURES:
The City will incorporate the following Mitigation Measures into the Project.
City of Brentwood Wastewater Treatment Plant Phase II Expansion Project Proposed Supplemental Mitigated Negative Declaration
Regarding Environmental Impact
3 Air Quality
Mitigation Measure AQ-1: Basic Best Management Practices for Construction-Related Fugitive Dust Emissions.
B-1. All exposed surfaces (e.g., parking areas, staging areas, soil piles, graded areas, and unpaved access roads) shall be watered two times per day.
B-2. All haul trucks transporting soil, sand, or other loose material off-site shall be covered.
B-3. All visible mud or dirt trackout onto adjacent public roads shall be removed using wet power vacuum street sweepers at least once per day. The use of dry power sweeping is prohibited.
B-4. All vehicle speeds on unpaved roads shall be limited to 15 miles per hour.
B-5. All roadways, driveways, and sidewalks to be paved shall be completed as soon as possible. Building pads shall be laid as soon as possible after grading unless seeding or soil binders are used.
B-6. All excavation, grading, and/or demolition activities shall be suspended when average wind speeds exceed 20 mph.
B-7. All trucks and equipment, including their tires, shall be washed off prior to leaving the site.
B-8. Unpaved roads providing access to sites located 100 feet or further from a paved road shall be treated with a 6- to 12-inch layer of compacted wood chips, mulch, or gravel.
B-9. Publicly visible signs shall be posted with the telephone number and name of the person to contact at the lead agency regarding dust complaints. This person shall respond and take corrective action within 48 hours. The Air District’s General Air Pollution Complaints number shall also be visible to ensure compliance with applicable regulations.
Biological Resources
Mitigation Measure BIO-1: General Construction Measures.
All contractors and equipment operators will be made aware of the ecological values of the site, and will be given instructions to comply with all mitigation measures.
Construction activities will be limited to a designated work area (including the work corridor and staging areas). The work area will be clearly identified and will be staked and flagged where necessary prior to initiation of construction activities. This will include flagging of riparian and wetland habitats in the vicinity of work areas to ensure their avoidance and protection.
All construction activities, including site preparation and development, will be restricted to City of Brentwood Wastewater Treatment Plant Phase II Expansion Project Proposed Supplemental Mitigated Negative Declaration
Regarding Environmental Impact
4 daytime hours between 6 a.m. and 5 p.m. on weekdays and non-holidays unless weekend work is unavoidable.
Mitigation Measure BIO-2: Participation in the ECCCHCP.
The City will participate in the ECCCHCP for the Proposed Project, if applicable to the work sites, to mitigate any potential impacts to special-status species covered under the ECCCHCP.
This coverage will allow the City to minimize and compensate for potential effects resulting from construction- and operation-related activities associated with the Proposed Project through implementation of all applicable conservation measures and compensation mechanisms of the ECCCHCP.
The City will conduct Planning Surveys, as necessary, according to the species-specific protocols contained in Section 6.3.1 of the ECCCHCP and will complete an Application Form and Planning Survey Report.
To compensate for unavoidable project-related effects the City will pay either the applicable fee or dedication of land in lieu of the fee as described in Chapter 9, Funding, and in Brentwood Ordinance number 850.
Mitigation Measure BIO-3: Special-Status Plants.
On suitable land cover types under the ECCCHCP, the City will conduct special-status plant surveys using approved CDFW/USFWS methods during the appropriate season for identification of covered and no-take plant species, as well as any additional special-status plant species not covered under the ECCCHCP.
If ECCCHCP-covered special-status plant species are found in the construction areas, the City would implement all applicable conditions on covered activities under the ECCCHCP including Conservation Measure 1.11 “Avoid Direct Impacts on Extremely Rare Plants” and Conservation Measure 3.10 “Plant Salvage when Impacts are Unavoidable.” If special-status plant species that are not covered by the ECCCHCP are discovered, mitigation measures to reduce impacts to less-than-significant levels would be developed in consultation with appropriate resource agencies.
Mitigation Measure BIO-4: Special-Status Amphibians and Reptiles.
The City will implement pre-construction surveys, as necessary per the ECCCHCP, for California tiger salamander, silvery legless lizard, western pond turtle, California horned lizard, giant garter snake, and San Joaquin whipsnake in annual grassland habitat for the construction areas at the WWTP.
Surveys will be implemented in accordance with methods described in Section 6.4.3 of the ECCCHCP.
If any ECCCHCP -covered species are found (California tiger salamander, silvery legless City of Brentwood Wastewater Treatment Plant Phase II Expansion Project Proposed Supplemental Mitigated Negative Declaration
Regarding Environmental Impact
5 lizard, western pond turtle, and giant garter snake), all applicable avoidance and minimization measures, construction monitoring, conservation measures, and/or mitigation fees of the ECCCHCP will be implemented.
If any special-status species not covered by the ECCCHCP (California horned lizard and San Joaquin whipsnake) are discovered, measures to reduce impacts to less-than-significant levels would be developed in consultation with CDFW.
Mitigation Measure BIO-5: Burrowing Owls.
The City will implement pre-construction surveys for burrowing owls or burrows at proposed construction sites with potential habitat in accordance with methods described in Section 6.4.3 of the ECCCHCP.
If the burrowing owls nests or burrows are discovered in the work areas, all applicable avoidance and minimization measures, construction monitoring, conservation measures, and/or mitigation fees for this species in the ECCCHCP will be implemented.
Mitigation Measure BIO-6: Other Special-Status Birds.
If construction activities are scheduled to occur between February 15 and September 15, preconstruction surveys will be conducted at proposed construction sites within 30 days prior to any such activities to determine whether any nests of special-status birds are present. A qualified biologist will search within 1000 feet of sites for raptor nests, and within 250 feet of sites for passerine nests. Biologists will conduct a visual and aural search of the survey area on foot, using binoculars to scan tree tops for the presence of raptor nests.
If any nests are identified, measures to reduce impacts to less-than-significant levels, such as species-specific buffers, would be developed in consultation with appropriate resource agencies (CDFW and/or USFWS).
Mitigation Measure BIO-7: American Badger.
The City will implement pre-construction surveys for American badgers or burrows at proposed construction areas with potential habitat in conjunction with burrowing owl surveys.
If any American badgers or burrows are found, measures to reduce impacts to less-thansignificant levels would be developed in consultation with CDFW, and/or mitigation fees for this species in the ECCCHCP will be implemented.
Mitigation Measure BIO-8: Bats.
The City will implement pre-construction surveys for bats roosts at proposed construction areas with potential habitat in conjunction with burrowing owl surveys.
If any bat roosts are found, measures to reduce impacts to less-than-significant levels would be developed in consultation with CDFW, and/or mitigation fees for covered bat species in the City of Brentwood Wastewater Treatment Plant Phase II Expansion Project Proposed Supplemental Mitigated Negative Declaration
Regarding Environmental Impact
6 ECCCHCP will be implemented.
Mitigation Measure BIO-9: Ringtail.
The City will implement pre-construction surveys for ringtail and their burrows at proposed construction areas with potential habitat in conjunction with burrowing owl surveys.
If any ringtail or ringtail burrows are found, measures to reduce impacts to less-than-significant levels would be developed in consultation with CDFW, and/or mitigation fees for this species in the ECCCHCP will be implemented.
Cultural Resources
Mitigation Measure CULT-1: Accidental Discovery of Archaeological Resources.
Note: this mitigation measure has been revised to provide specificity regarding where work can and cannot occur in the event of discovery of potential archaeological resources.
If any prehistoric or historic artifacts, or other indications of archaeological resources such as unusual deposits of stone, bone or shell, stone artifacts, or historic trash deposits or foundations are discovered once ground-disturbing activities are underway, work shall be halted within 50 feet of the find(s) and a qualified archaeologist (i.e., an archaeologist that meets the qualifications at 36 CFR Part 61) shall be retained to assess its potential significance. If the find is not significant, then no additional cultural resources investigations are necessary and Project work may resume in the area of the find. If the find is determined to be a historical or unique archaeological resource, contingency funding and a time allotment to allow for implementation of avoidance measures or appropriate mitigation shall be made available, as provided in §15064.5 of the CEQA Guidelines. Work may continue on other parts of the project site while historical or unique archaeological resource mitigation takes place on-site.
Mitigation Measure CULT-2: Accidental Discovery of Paleontological Resources.
A qualified professional paleontologist shall periodically monitor excavations to check for fossils that may be unearthed. If vertebrate fossils (e.g., teeth, bones) are unearthed by the construction crew anywhere on the project, the finds should be set aside and all excavation activity cease at the specific place of discovery until the paleontologist has assessed the find and, if deemed significant, salvaged the find in a timely manner. The decision to conduct paleontological salvage operations will be determined by the paleontologist in consultation with city staff. Work may proceed on other parts of the project while assessment and/or salvage by the paleontologist is underway. Finds determined significant by the paleontologist shall be conserved and deposited with a recognized repository such as the University of California Museum of Paleontology.
City of Brentwood Wastewater Treatment Plant Phase II Expansion Project Proposed Supplemental Mitigated Negative Declaration
Regarding Environmental Impact
7 Mitigation Measure CULT-3: Accidental Discovery of Human Remains.
Note: this mitigation measure has been revised to provide specificity regarding where work can and cannot occur in the event of discovery of human remains.
In the event of the accidental discovery or recognition of any human remains, all work within 100 feet of the find shall cease immediately until compliance with the provisions of §15064.5(e)(1) and (2) of the CEQA Guidelines has occurred. The CEQA Guidelines specify that in the event of the discovery of human remains other than in a dedicated cemetery, the Contra Costa County Coroner must be notified to determine if an investigation into the cause of death is required. If the coroner determines that the remains are Native American, then, within 24 hours, the coroner must notify the Native American Heritage Commission, which in turn will notify the most likely descendant who may recommend treatment of the remains and any grave goods. If the Native American Heritage Commission is unable to identify a most likely descendant or the most likely descendant fails to make a recommendation within 24 hours after notification by the Native American Heritage Commission, or the landowner or his authorized agent rejects the recommendation by the most likely descendant and mediation by the Native American Heritage Commission fails to provide a measure acceptable to the landowner, then the landowner or his authorized representative shall rebury the human remains and grave goods with appropriate dignity at a location on the property not subject to further disturbances.
Geology and Soils
Mitigation Measure GEO-1: Conduct Geotechnical Investigation and Implement Recommended Measures.
The City will conduct a geotechnical investigation for the Proposed Project that evaluates sitespecific conditions related to the potential for ground rupture, risk to features due to ground shaking, risk of soil liquefaction, and risk of expansive soils. Based on subsurface conditions, the pipelines and appurtenances will be designed to withstand the effects of strong ground shaking and the effects of soil liquefaction.
Based on the results of the geotechnical investigation, the City and its contractor(s) will be responsible for implementing the design specification and performance criteria according to Uniform Building Code (UBC) the City’s Seismic Hazards policies for pipeline construction, trenching, backfill materials, and other recommendations.
City of Brentwood Wastewater Treatment Plant Phase II Expansion Project Proposed Supplemental Mitigated Negative Declaration
Regarding Environmental Impact
8 Hydrology and Water Quality
Mitigation Measure HWQ-1: Implement Construction BMPs for Water Quality Protection.
The City, or its designated general contractor, shall obtain authorization of project construction activities under the SWRCB’s NPDES Construction General Permit (Order No. 2009-0009- DWQ/NPDES Permit No. CAS000002, and any applicable amendments), for any activities not subject to exemption from the permit. The Stormwater Pollution and Prevention Plan (SWPPP) prepared for permit will describe the BMPs that will be used to avoid and minimize potential construction-related contaminant discharges at construction sites. Compliance with this mitigation shall be included as a condition of the construction contract(s) between the City and applicable construction contractor(s), and as appropriate, shall additionally be included in final project designs and specifications that are prepared for the Proposed Project. The City will be responsible for ensuring that the construction is implemented in accordance with the Construction General Permit.
Mitigation Measure HWQ-2: Dissolved Oxygen Evaluation and Control Measures.
Upon initiation of increased recycled water deliveries for the Proposed Project, the City shall evaluate Marsh Creek for adverse DO-related effects to the fish community, and implement control measures, if necessary. During periods when recycled water is being distributed from the WWTP during the mid-summer months (i.e., July and August), and background Marsh Creek streamflow levels are low, the City will monitor receiving water DO to determine whether DO falls to levels that may result in adverse effects to fish and invertebrates within lower Marsh Creek. If potentially adverse DO levels are observed from monitoring, the City will implement fish and invertebrate surveys upstream and downstream of the WWTP discharge to determine whether actual adverse effects (e.g., reduced species diversity, change in expected community structure, loss of sensitive organisms) are occurring. Should adverse effect be identified through field surveys that are determined to be attributable to the reduced effluent discharge, the City shall implement corrective measures to substantially reduce or eliminate the adverse effects. Such corrective measures include, but may not be limited to, reducing the amount of water used for recycled water irrigation.
City of Brentwood Wastewater Treatment Plant Phase II Expansion Project Proposed Supplemental Mitigated Negative Declaration
Regarding Environmental Impact
9 Noise
Mitigation Measure NZ-1. Minimize Construction-Related Noise.
To reduce noise-related impacts to occupants of nearby residential land uses, the following BMPs will be incorporated into the plans and design of the Proposed Project:
Noise-generating construction activities will be limited to the weekday and weekend restrictions specified by the City’s Municipal Code. All construction equipment will be required to have sound-control devices no less effective than those provided on the original equipment. No equipment will have an unmuffled exhaust system.
Additional noise-reduction measures will be implemented as appropriate and practical, including but not limited to: (a) locating staging areas and stationary construction equipment as far away from sensitive receptors as feasible and direct noise emissions away from receptors; (b) limiting equipment idling time; and (c) notifying nearby residents 48 hours in advance of starting construction in an area not previously affected by recent construction activities.
Require construction contractor to have a designated “noise disturbance coordinator” who will be responsible for responding to noise complaints, determining the causes of the noise, and instituting reasonable measures (as warranted) to correct the problem.
Tribal Cultural Resources
Mitigation Measure TCR-1. Incidental Discovery of Tribal Cultural Resources.
Note: this is a new mitigation measure to address potential additional effects to tribal cultural resources.
If resources of Native American origin are discovered once ground-disturbing activities are underway, the City shall contact local Native Americans to consult on the find. If the find is determined to be a tribal cultural resource, contingency funding, and a time allotment to allow for implementation of avoidance measures or appropriate mitigation determined in consultation with local Native Americans shall be made available. Work may continue on other parts of the Proposed Project site while tribal cultural resource mitigation takes place.
9. FILING LOCATION:
A copy of the Supplemental Initial Study regarding the environmental effect of the Project is on file at City of Brentwood Department of Public Works, 150 City Park Way, Brentwood, CA 94513.
City of Brentwood Wastewater Treatment Plant Phase II Expansion Project Proposed Supplemental Mitigated Negative Declaration
Regarding Environmental Impact
10 10. THIS STUDY WAS:
Adopted as presented.
Adopted with changes. Specific modifications and supporting reasons are attached.
The City Council of the City of Brentwood held a public hearing on this Mitigated Negative Declaration on November 14, 2023, at 7:00 p.m.
11. DETERMINATION:
On the basis of the whole record, including the original Initial Study prepared in 2016 for the Project, the Supplemental Initial Study of environmental impact of the Project prepared in 2023, and comments received, the Project could have a significant effect on the environment but will not in this case because of incorporation of additional mitigation measures described in Item 8 above that are by this reference made conditions of Project approval, along with the mitigation measures already incorporated into the Project by Resolution 2016-109. A CONDITIONAL NEGATIVE DECLARATION is hereby adopted.
__________________ ____________________________________ Date Tim Ogden, City Manager
City of Brentwood